class Solution
{
public:
    int MLS(vector<int> &arr)
    {
        sort(arr.begin(), arr.end());
        int n = arr.size(), ret = 0;
        for (int i = 0; i < n;)
        {
            int j = i + 1;
            int count = 1;
            while (j < n)
            {
                if (arr[j] - arr[j - 1] == 1)
                {
                    count++;
                    j++;
                }
                else if (arr[j] - arr[j - 1] == 0)
                {
                    j++;
                }
                else
                    break;
            }
            ret = max(ret, count);
            i = j;
        }
        return ret;
    }
};